Windshield Repair

Aside from replacing windshields, under certain conditions there is the less expensive possibility of repairing a windshield that has been damaged by a stone.

Tinted windshields, windshields with colored liners or insulated glass (Audi A8, A6) can be repaired because the tint is created with colored intermediate foil.

Repairing the windshield is preferred to replacing it under the following conditions.

Special tools

Required special tools, workshop equipment, testing and measuring equipment, and aids

Fig 1: Windshield Repair Set VAS 1993

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Window repair kit VAS 1993

Contains the following tools:

Fig 2: Windshield Repair Set (VAS 1993) Components

Courtesy of VOLKSWAGEN UNITED STATES, INC.

1 - Transformer

2 - 1 set resin gauges

3 - Mirror

4 - Suction hook

Use as vacuum pump

5 - Tool carrier

6 - Injector

After first use in opaque packaging

7 - Resins for at least 15 applications

8 - 12V drill machine

9 - Drill and polish set

10 - Awl

11 - UV lamp

12 - Foil

13 - Battery connector cable

Conditions

The damage location must not lie within the drivers direct field of vision - 1 -. This field corresponds to a strip about 29 cm wide (DIN A4 format across) central to the drivers line of sight in direction of travel, bordered above and below by the windshield washer field.

Fig 3: Identifying Field Of Vision & Damaged Area On Windshield

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Cracks radiating out from the point of damage - 2 - must not be longer than 50 mm and/or continue outward into the peripheral area.

The diameter of the point of damage - 1 - must not be larger than 5 mm.

Fig 4: Identifying Windshield Layers

Courtesy of VOLKSWAGEN UNITED STATES, INC.

The intermediate foil - 2 - or interior glass - 3 - must not be damaged.

There must not be any dirt or moisture penetrating into the lower area of the crack.

Therefore, the date of damage should not date back very long.

The following damage may be repaired as long as it is not in the field of vision or in the peripheral areas of the windshield:

Fig 5: Identifying Bulls Eye Damage

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Bulls eye

Fig 6: Identifying Combination Break Damage

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Combination break

Fig 7: Identifying Star And Crack Damage

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Star and crack

Repair description

Repairs should not take place in direct sunlight.

The repair location must be room temperature.

The work area must be protected against moisture.

Fig 8: Preparing Penetration Point With Scriber

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Loosen impact area with hard metal awl but do not expand it or remove any glass fragments.

Remove any possible moisture with suction hooks while helping with hair dryer from inside. Stop repair if moisture cannot be removed.

Mount mirror - 1 - on inside and align so location of damage can be seen clearly.

Fig 9: Installing Mirror, Holder & Injector

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Mount tool carrier - 2 - with injector - 3 - so injectors rubber seal lies directly over point of impact. Check by looking in mirror.

Fig 10: Removing Threaded Spindle Completely From Injector

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Completely remove threaded spindle - 2 - from injector - 1 -.

Fill injector - 1 - with 2 to 3 drops resin (this amount is resin is sufficient for any damage).

Return resin bottle to package immediately because resin is UV sensitive.

Wait until resin advances into rubber seal.

Tighten injector - 1 - by turning threaded spindle - 2 -. The correct pressure is achieved when the impact point turns clear from the center out.

NOTE:

The resin penetrates into the cracks very slowly and may not be visible right away.

Wait 10 minutes, then release injector to end of threads.

Hold injector tightly when loosening so that it does not slip.

Repeat procedure (at least 3 times) until all air is removed from damage location. You can recognize this by the fact that all of the cracks will no longer be visible. Tightening the injector creates pressure up to 18 bar.

Note in mirror when the damage location is filled. Then end injection.

Then swing carrier with injector to side and check whether resin has flowed into all points of fracture.

Remove any possible trapped air with the suction hook placed on the repair location.

Fig 11: Applying Foil

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Cut cover foil - 1 - keep ready. Remove injector with tool carrier and lay cover foil immediately on damage location (do not press down) to prevent air from entering. The foil contains an activator to dry the resin.

Immediately return injector to packaging because resin is UV sensitive and can be reused for the next repair. Replace tool carrier in released position in case and remove mirror with mount.

Fig 12: Securing UV Lamp

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Secure UV lamp - 1 - over damage location. Allow UV light to act on resin for 10 minutes, then remove UV lamp.

Smooth out damage location with removal blade and possibly polish with 12 Volt drill machine and polishing set.

NOTE:

After the repair, the vehicle is ready to operate again without any waiting time.
Traces of fractures cannot be removed completely with many types of breaks but they do not affect the results of the repair.
After repair, the window is as strong as normal and further cracks are prevented by the molded and hardened plastic resin. The hardened resin is colorless and has the same refraction index as glass.